- District crime squad inspector Sheung Sing (Benjamin Yuen), a rising star in the police force, is shot in the head while trying to save a colleague, which changes his entire life. Having a miraculous recovery, he works twice as hard and is dubbed "Hard boiled cop" but suffers severe sequelae!
Chief Superintendent Man Hei Wah (Kara Wai) of the Kowloon West Regional Police Headquarters is very ambitious, looking to become the first female Commissioner of Police. The one who shot Sheung Sing turns out to be Yau Bing Go (Philip Keung), an undercover cop for Hei Wah. When it comes to investigating cases for Hei Wah, Bing Go knows no bounds. Yet, in the power struggle against another Chief Superintendent Kan Kwok Chu (Hui Shiu Hung).
Hei Wah went back on her word, which made Bing Go so furious that he shot at Hei Wah, but accidentally injured Sheung Sing. The gunshot incident turns Bing Go into a defector. Shrouded in guilt towards Sheung Sing, Bing Go secretly helps him solve cases as redemption. Being used as pawns in political power struggles, Sheung Sing and Bing Go fortunately get help from Chief Superintendent Ching Yu Sum (Ben Wong) of the Complaints and Internal Investigations office, vowing to end this once and for all...